Most boaters throw a "canned" first aid kit in a locker and hope they'll never have to open the lid. However, things change. Each time you leave the dock you play by different rules according to where you are both nautically medically.

On your last doctor visit were you advised to start or stop taking aspirin? Does your new prescription make you more sensitive to sunburn? Do you need a self-administered shot immediately if you eat a peanut or are stung by a bee? Do you cruise areas where swimmers get jellyfish stings or hikers get poison ivy? Your medical situation can change as often as your location, and a good first aid kit reflects those changes.

Rule One is to know your medical history, so start with a small notebook or flash drive filled with medical and dental contact numbers, health policy numbers, lists of prescriptions you take, results of your last important tests, and other common-sense items. Rule Two is to customize the kit according to your special needs, such as glucose tablets for hypoglycemia, child-size meds for kids and things the vet recommends for pet emergencies.

Talk to your doctors, get a good first aid manual for quick reference, and make note of two hotlines: 888-222-1222 for Poison Control and 888-425-4435 to ask if something your pet just ate will be injurious. Then assemble your kit over time. This list is by no means definitive, but it should get you thinking.

WALK THE ISLES

Some boaters start with a ready-made kit and add to it. First aid kits are widely available, including some made on a custom basis especially for boaters by companies like OceanMedix (see link). Less advanced but worth looking at it is ReadyFreddy (readyfreddy.com). Used by paramedics it contains 84 essential items in a sturdy, grab-able backpack. Inside, supplies in five smaller bags include items for treating illness and injury plus emergency lighting, a hand charger for cell phones, a wind-up radio and other emergency communications items. Nothing requires batteries.

Standard medications such as aspirin and pain relievers such as Tylenol or Motrin, as well as anti-seasickness pills, should be onboard. So should Band-aids and bandages, medical tape, antibiotic ointment, burn cream, antiseptics and other common first aid items. A walk through the drug store helps.

You'll also want a bag or carrier that is roomy, easily organized and waterproof to keep your materials in. It should be stored someplace easy to find and it should be handy to grab. Outdoor stores sell many bags that may fit the use.

Cathy Landberg, R.N., offers emergency kit checklists at her website, safety-tape.com. Her high-tech reflective tape is sold to first responders and other professionals. With a roll of reflective tape you can instantly turn your first aid kit – or anything else – into something reflective and visible. Her tape is costly but it's tear-able, can be written on, is waterproof and has other features. Cheaper reflective tapes can be found in automotive, hardware and bicycle stores but may not be waterproof.

California paramedic Rod Brouhard says everyone "should learn CPR, carry a cell phone, have medical information with you and keep a calm head." Go to FirstAid.About.Com for Rod's advice.

Beth Whitman, author of Wanderlust and Lipstick travel guides for women, listed all her recommendations including some offbeat items that don't usually come in ready-made first aid kits: nail clippers, large and small zip-top bags, cough drops and, if you have toddlers on board, diaper rash cream and teething gel. Go to wanderlustandlipstick.com.

DON'T LEAVE HOME WITHOUT...

"Add a small supply of travelers checks to the first aid kit," advises American Express spokesperson Joel Kaiman. Extra cash might be needed for a medical emergency, such as an all-night pharmacy that doesn't accept credit cards. Cruising sailors can't always cash personal checks.

David Sweeney, O.D. of InSight Vision Source in Atlanta, says, "I recommend carrying antibiotic eye drops such as Vigamox or Zymar in case of red eye, especially for contact lens wearers."

"Don't forget food and water," says Howard Wallace, president of emergency preparedness company Survivor Industries. "In an evacuation where you have only enough time to grab an emergency kit, they could make a difference." To see the company's pre-designed emergency kits, go to survivorind.com.

In burn cases, "You can hold a hand under a faucet," says Dr. Daniel Rifkin. But who has unlimited running water on board? And how can you fit a shoulder or hip under a faucet? Dr. Rifkin, pediatrician at Penn State Children's Hospital and former volunteer firefighter, recommends Burn Jel Plus. The gel transfers heat away from the burn, much as running water does, and also contains Lidocaine for pain relief. Find it at major drug chains.

With a compact Personal Oxygen Device (POD) costing less than $20, you can administer 40 to 50 life-giving breaths. Get information at http://go2air.com/.

Air Med is an air-evacuation company that owns its own fleet of airplanes and whisks you to the hospital of your choice any time you have a medical emergency more than 150 miles from home. Family coverage costs as little as $350 per year and it's good worldwide. Go to airmed.com for information.